Lord Justice Leveson will find out whether newspapers are divided or united over proposals for a new press regulator that will be able to levy fines of up to £1m for breaches of ethical standards.

He has used his powers under section 21 of the Inquiries Act 2005 to order newspaper editors to say whether they agree with the detailed proposals submitted last month by Lord Black of Brentwood for regulation of the press.

Black, the chairman of the Press Standards Board of Finance, will appear as a witness on Monday when the inquiry resumes for its final phase which centres on future press regulation. Also appearing on Monday is Lord Hunt, the chairman of the Press Complaints Commission, which is being phased out.

Black set out plans last month for what he described as an "entirely different" regulator with a new structure and powers to punish errant newspapers and incentives to ensure every newspaper agrees to supervision.

Richard Desmond's Daily Express and Daily Star, which are not in the current PCC system of regulation, would under the new system risk being banned from taking advertising and using Press Association news wire services if they did not join the proposed regulator.

These proposals are unlikely to have unanimous backing by newspaper editors and the body for the Incorporated Society of British Advertisers has already questioned how a ban on advertising for errant newspaper owners could work in practice.

Next week the inquiry will also hear from other regulators including the Irish ombudsman, Professor John Horgan, and Ed Richards, the chief executive of Ofcom.

Horgan and Hugh Tomlinson QC, who has been involved in behind-the-scenes roundtable discussions among newspaper groups on future reforms, will give evidence on Friday as will Professor John Curran and Angela Phillips of the Co-ordinating Committee for Media Reform.

The National Union of Journalists general secretary, Michelle Stanistreet, will appear at Leveson on Tuesday when Martin Moore of the Media Standards Trust is also giving evidence.